Repeating apparatus for concentration units



- May 12, 1931. O ATHERTQN 1,805,351

REPEATING APPARATUS FOR CONCENTRATION UNITS 'Filed Sept. 16, 1929 2Sheets-Sheet 1 Position A/a. 1 Single Line Re eawr fonliizrajor Mac/(Pa7161 J 3 7% INVENTOR ALBERT/THEE 7'0/v TTORNEY May 12, 1931. A. ATHERTONREPEATING APPARATUS FOR CONCENTRATION UNITS 2 Sheets-Sheet 2 Filed Sept.16, 1929 %Z INVENTOR ALBERT A THER ro/v Patented May 12, 1931 r PATENTFICE ALBERT ATL'ERTGN, F BLOOMFIELD, NEW JERSEY, ASSIGNOR TO THE WESTERNUNION TELEGRAPH GGEHPANY, OF NEVJ' YORK, N. "3C, A CORPORATION OF N EWY'ORK REPEATING APPARATUS FOR (BONCENTRATION UNITS Application filedSeptember 16, 1929. Serial No. 393,052.

This invention relates to a circuit arrangement for handling the traiiicof a number of telegraph lines terminating at a central station andhaving diiierent characteristics, by means of telegraphic printers, suchas the socalled simplex printers or other telegraphic receiving andtransmitting apparatus having definite operating characteristics.

It is the practice at the present time in central stations having alarge number of lines terminating therein to employ what are known asconcentration units in order to reduce the number of operators requiredto conveniently handle the traffic.

A concentration unit briefly comprises an arrangement whereby a largenumber of underloaded line circuits are grouped in front of each of asmaller number of operators so that an operator at any position maycut-in her receiving and transmitting apparatus on any line to transactbusiness thereover. A suiiicient number of positions are provided toenable the maximum traffic to be handled. As the traffic decreases involume the surplus operators may be released thus permitting the totalvolume or" traflic on all lines to be operated by from one operatorupwards to the maximum number of operators "for which there areavailable positions, depending upon Pailic conditions.

It is advantageous in telegraph systems to employ concentration unitshaving a large number of lines terminating at the concentrator with aproportionate number of positions, since the average delay incident tothe answering of an incoming call signal on any line decreases as thenumber of possible positions at which it may be answered, increases.However, as the number of positions increases and the system becomesmore complex, certain problems arise in connection with the expeditioushandling of the trallic, such as the determination of which operatorshall answer the call signal, indications as to which lines are busy,proper distribution of the traf fic among the various positions, etc,and the solution of these problems has imposed certain inherentcharacteristics on the concentra-tion units.

-One arrangement which is adaptable to the handling of a large number oflines at each of a large number of positions and to which the presentinvention particularly reates is fully disclosed in a copendingapplication of H. Vt. Drake and WV. B. Bla-nton, Serial No. 336,617,filed January 31, 1929. In this arrangement, the circuit connections aresuch that when a printing and transmitting unit at any position iscut-in on a trunk of a concentrator, battery of negative polarity isapplied to the line and when the line is idle, that is, when there is noprinter con-- nected to the line the concentrator automatically appliesbattery of positive polarity to the line. The connection of battery ofopposite polarity to the line when a printer is cutin and when it iscut-out is inherent in the construction of the concentrator and isprimarily for the purpose of operating the necessary busy line testsignals and to prevent a second printer from being operated when cut-inat any position if the line is in use at another position of theconcentrator.

Since the printers operate only on make and break signals, reversals ofthe line polarity do not affect their operation, both polarities servingto hold the line closed at the out station. However, this charactersticof the concentrator of reversing the polarity of the line prevents itsdirect connection to aline of such length as to require battery at bothends since if it were so connected, the line would stand open orsubstantially so when the concentrator appliedbattery of the samepolarity as that applied by the out station. In accordance with myinvention in order to terminate such long lines in a concentrator Iprovide a repeater at the central station intermediate the line and theconcentrator, for applying battery of the same polarity to the lineirrespective of the polarity applied at the concentrator.

It will be appreciated, since any operator may be called upon to cut-inon any one of I a hundred or more lines of different lengths andcharacteristics and receive thereover with the same apparatus that inorder to avoid the necessity of readjusting the apparatus each time achange is made from one line to another, the signals should betransmitted to each printer with substantially equal strength andcompleteness or attenuation. By the provision of a repeater at thecentral station for each line terminating at the concentrator, I am ableto operate the printers under substantially uniform conditions over allof the lines.

The repeater may be a single line repeater, a duplex half repeater or aterminal duplex repeater.

It is desirable in certain instances to employ polar line relays inthese repeaters, responsive to the signals originating at tieconcentrator and it is necessary that such relays remain on theirmarking contacts whenever the line is closed, regardless of whetherpositive or negative battery is applied at the concentrator. Thisrequirement is met, in accordance with one embodiment of my invention,by providing pole changing means associated with such polarized relays,responsive to reversals of polarity at the concentrator, for maintainingthe current in the same direction through the operating winding of therelay and hence to hold the movable contact of the polarized relay onits marking contact, wnen battery of either polarity is applied at theconcentrator= From the foregoing it will be understood that theprincipal objects of the invention are to permit long lines havingbattery at each end to be terminated at a concentrator unit at whichreversals of current occur; to provide signals of substantially uniformstrength at the concentrator for each of a number of lines so thattratlie can be handled over any of such lines by the same printing orother receiving apparatus without readjustment thereof and further,where polarized relays are employed in carrying out the above objects,to prevent the improper operation of such polarized relays by reversalsin polarity originating at the concentrator.

Other objects and advantages will hereinafter appear.

In order that a full understanding of the invention may be had referenceis made to the accompanying drawings in which;

Fig. 1 is a circuit diagram illustrating a single concentrator positionwith a single line repeater associated with one line terminating at theconcentrator.

Fig. 2 is a similar diagram in which polarized line relays are employedin the repeater and provided with means for maintaining the contactsthereof on marking when the concentrator is connected to battery ofeither polarity and;

Figures 3 and 4 are circuit diagrams showing modified arrangements formaintaining the polarized relays on their marking contacts when theconcentrator is connected to the battery of either polarity.

Referring to Figure 1, I have shown one position of a concentrator withthe signal circuits, motor operating circuits and other auxiliarycircuits omitted. Each position includes, as essential elements, aprinting and transmitting unit and a concentrator jack panel 11. Theprinting and transmitting unit comprises a driving motor 12, the circuitof which is completed by mechanism not shown when the printing andtransmitting unit is connected to a line, a keyboard 13, a series oftransmitting contacts 1 1- controlled by said keys and a printing magnet15. The concentrator jack panel has a plurality of jacks A, B, C, D,etc., one for each line terminating at the concentrator. While only fourof such jacks have been illustrated it will be understood that with ahundred wire concentrator there will be one hundred acks for eachposition. The printing unit may be selectively connected to any of theline jacks by a cord 16 and plug 17 hen the plug 17 is free of anyparticular jack, battery of positive polarity is applied. to the trunk18 connected to such jack through auxiliary jack contact 19 and when theplug is inserted to cut-in a printer on the line contact 19 is openedand negative potential is applied to the trunk 18 from a generator 20,normally closed transmitter contacts 21 of the distributor 14:, printermagnet and cord 16 to the plug 17.

As stated above a repeater is interposed between the trunk 18 and theline L in connection with each line for the purpose of enabling longlines having battery at each end to terminate at the concentraior and toprovide uniform operating conditions for the printer over all lines.

The particular arrangement of the single line repeater shown in Figure1, forms no part of the present invention, aside from the combinationthereof with the concentration unitand only a. general discriptionthereof will be given.

The repeater consists of two line relays 22 and 23 and two associatedpolar t ansmitting relays 24 and 25. The line relays 22 and 23 each havean operating magnet- 26 and 27 respectively and a locking magnet 28 and29 respectively. The winding of operating magnet 26 is connected to thetrunk 18 and to the marking contact 30 of transmitting relay 24. Thewinding of the operating magnet 27 of line relay 23 is connected fromthe line L through the marking contact 31 of the transmitting relay 25and through a generator 82 to the ground 33. Each of the line relays 22and 23 has a grounded armature 34 and 35 respectively.

With the key at the outer sta lion closed and positive potential appliedto the trunk 18 at the concentrator, the operating windings of both linerelays 22 and are energized and hold their tongues 3 1 and 35 againstthe front contacts. The locking windings 28 and 29 are unenergized atthis time dueto the grounding of generators 36 and 37 through the relaytongues 34 and respectively. The tongues of the transmitting relays areboth held on their marking contacts by current flowing from the groundthrough generators 38 and 39, conductors 40 and 41 and windings 42 and43 respectively of the relays 25 and 24, to the ground at 44, through aresistance 45.

If the printer unit is cut-in at the concentrator so as to applynegative battery to the trunk 18 the position of the movable contacts ofthe transmitting relays is not affect ed since the line relay 22 is ofthe non-polarized type.

However, whenthe distributor contacts 14 are opened to transmit aspacing signal, the tongue 34 of the line relay 22 leaves its frontcontact, thus permitting the generator 36 to become effective toenergize locking magnet 29 to hold the relay tongue 35 on its frontcontact. Upon contact of the relay tongue 34 with its back contact,generator 38 is grounded through the relay tongue and is no longereffective to hold the tongue of the transmitting relay 25 on its markingcontact. At the same time a second path to the ground is provided forcurrent flowing through the winding 43 of relay 24 namely through thewinding 42 of relay 25 conductor 40 and tongue 34 of relay 22. Thedirection of this current is such as to move the tongue of thetransmitting relay 25 to its spacing contact thus transmitting a spacingsignal to the line L.

lVhen the line relay is again energized by closing of the transmittingcontacts of the printer 10 the tongue 34 of the line relay 22 returns toits front contact and marking current is again'applied to the line,through the marking contact 31 of relay 25.

It will be noted, due to the presence of the generator 32 in the linecircuit, that battery of constant polarity is applied to the lineregardless of whether the concentrator is applying positive or negativebattery to the trunk 18 and thus this battery may be used to assist thebattery applied at the out station. It should be further noted, thatincoming line signals repeated by. the relay 24 are of uniform strength,as determined by the potential of the battery applied at theconcentrator, irrespective of the length of the line. The printer will,therefore, be operated under uniform conditions from each lineterminating at the concentrator. V

. In Figure 2 I have shown a single line re.- peater similar to thatshown inFigure 1 eX- cept that polarized'line relays 46 and 47 have beenemployed in place of the single current line relays 22 and 23 ofFigure 1. The spacing bias required for each line relay is applied bygenerators 48 and 49 connected in parallel with the ground connections50 and 51of the biasing. windings 52 and 53 with which each of thepolarized-relays. is provided. When the tongue of a line relay is on itsmarking contact, the locking or biasing circuit of the opposite linerelay, instead of being deenergized as in the case ofthe looking magnets28 and 29, of Figurel, is energized by current from the generators 48and 49 in such direction as to give the relay a spacing bias. 4

The operating winding 54 of the line relay 46 is connected to the trunkline 18 through a pole changing arrangement which responds to reversalof polarity produced at the concentration unit to reverse the terminalcon nections of the operating winding and thus to maintain the directionof current through the winding the same. The tongue of the polarizedrelay is thus held on its marking contact when current of eitherpolarity is applied at the concentrator.

The pole changing apparatus comprises a polarized relay 55 and a singlecurrent relay 56, the latter havingtwo movable armature tongues 57 and58, each of which plays between two fixed contacts. The back contact oftongue 57 and the front contact of tongue 58 are connected to oneterminal of the operating winding 54 of the polarized rela 46. The frontcontact of tongue 57 and back contact of tongue 58' are connected to thetongue of the transmitting relay 24. Relay tongue57 is connected to oneterminal of the winding of-relay 55, the opposite terminal of which isconnected to the trunk 18 and relay tongue 58 is connected to groundat'59;

One side of the winding of relay 56 is connected to the ground at 60 andthe otherside is connected to the right hand contact 61 of the polarizedrelay 55. The contact tongue of relay 55 is grounded at 62 through agenerator 63.

When the line is idle and hence when positive battery is being appliedat the concentrator, the tongue of relay 55 is held on its lefthandcontact and the tongues of relay 56 are consequently on their backcontacts-.-

The circuit for the operating winding of the line relay 46 is thencompleted from the trunk line 18 through the winding of the relay 55,back contact of relay tongue 5'7, operating winding 54 of the linerelay, marking contact 30 of transmitting relay 24 and back contact ofrelay tongue 58 to the ground at 59. The direction of current throughthe winding54 is such as to maintain the tongue of the relay on itsmarkingcontact. Upon reversal of current at'the concentrator the tongueof relay 55 moves to its righthand contact 61, thus energizing relay 56and moving contact tongues 57 g and 58 to their front contacts. Thisreverses the connections of the operating winding 54 of the line relayso that the direction of current is maintained the same through thewinding 57 and hence so that the tongue of the relay is held on itsmarking contact. It will be noted, therefore, that reversals of currentapplied at the concentrator do not affect the operation of the polarizedline relay. When a break in the circuit occurs at the concentrator, asin the transmitting of spacing signals, the tongue of polarized relay 46moves to its spacing contact due to the spacing bias applied by itsbiasing winding 52.

In Figure 3 I have shown a modified arrangement for maintaining thetongue of the polarized relay on its marking contact when current ofeither polarity is applied at the concentrator; Two operating windings 6k and 65 are provided for the line relay 46, each having their oppositeends grounded at 66 (as through the transmitting relay 24). The oppositeend of winding 64 is connected to the marking contact 67 of thepolarized relay and the opposite terminal of the winding is connected tothe spacing contact 68 of the relay 55. The tongue of relay 55 isconnected to the trunk 18 and the windingot the relay is also connectedto the trunk and to the ground through a resistance 69.

The connections of windings'64 and 65, to the contacts of relay 55 aresuch that current therethrough will always be in a direction to maintainthe tongue of the relay on its marking contact regardless of. thepolarity of the current applied at the concentrator. biasing winding 70is provided for moving the tongue to its spacing contact when thecircuit is opened.

In Figure 4 a still furtherv modification is shown for rendering thepolarized relay unresponsive to changes in polarity applied at theconcentrator. The polarized line relay 46 is provided with a singleoperating winding 71, the opposite ends of which are connected to thespacing and marking contacts; of the polarized relay 55 and also to theground through equal resistances 7.2 and 7:3. Heversal of the directionof current produced at the concentrator causes reversals in theconnections of the winding 71 so that the direction of current in thewinding 71 is maintained the same.

It 15 obviousthat various other means may be provided for maintainingthecurrent 1n a constant direction through the winding of:

the polarized relay, as for instance by means of rectifiers and sincevarious other changes may be made in the arrangement shown and describedwithout departing from the invention I do not desire to be limited to,the exact details illustrated except in accordance with the appendedclaims.

What I claim is:

1. The combination with a concentration unit having a telegraph printerassociated therewith, of a number of telegraph lines terminating at saidconcentration unit, repeaters intermediate certain of said lines andsaid conaoasar centration unit, means at the concentration unit forreversing the polarity of current applied to the repeaters and means forsupplying current of uniform polarity from said repeaters to the lineswhen current of either polarity is applied at the concentration unit.

2. The combination with a concentration unit having a telegraph printer,of a number of telegraph lines, having different characteristics,terminating at said concentration unit, a repeater employing a polarizedline relay interposed between each of certain of said lines and saidconcentration unit and means intermediate said concentration unit andrepeater for preventing changes in polarity, applied at theconcentration unit, from affecting the operation of said polarizedrelay.

3. The combination with a concentration unit having a telegraph printer,of a number of telegraph lines, having different characteristics,terminating at said concentration unit,

a repeater employing a polarized line relay interposed between each ofcertain of said lines and said concentration unit and means forpreventing changes in polarity applied at the concentration unit fromaffecting the operation of said polarized relay.

4. The combination with a concentration unit, having a receiving andtransmitting apparatus associated therewith, of a number of telegraphlines terminating at said concentration unit, repeaters interposedbetween certain of said lines and said concentration unit, means at theconcentration unit for supplying current of either polarity to therepeaters, a polarized line relay for certain of said repeaters havingan operating winding responsive to current applied at the concentratorand pole changing means for said polarized relay operable by reversalsof polarity applied at the concentration unit for reversing theconnection of said winding.

5. The combination with a concentration unit having receiving andtransmitting apparatus associated therewith, of a number of telegraphlines terminating at said concentration unit, repeaters interposedbetween certain of said lines and said concentration unit, means at theconcentration unit for supplying current of either polarity to therepeaters, a polarized line relay for certain of said repeatersresponsive to current applied at the concentrator and means responsiveto changes in direction of the current applied at the concentration unitfor maintaining the movable contact of said polarized relay in the sameposition when current of either polarity is applied at the concentrationunit.

In testimony whereof I aiiix my signature.

ALBERT ATHERTON.

